function testpartition4(A,fig)
n = size(A);
sn = round(n/4);
% L1 = A(1:sn, 1:sn);
% L2 = A(1:sn, sn+1:2*sn);
L3 = A(1:sn, 2*sn+1:3*sn);
% L4 = A(1:sn, 3*sn+1:4*sn);
% S1 = svd(L1);
% S2 = svd(L2);
S3 = svd(L3);
% S4 = svd(L4);
figure(fig);
% semilogy(S1, 'r');
% hold on
% semilogy(S2, 'b');
semilogy(S3, 'k');
hold on
% semilogy(S4, 'g');

